coreutils: The uniq command

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1 The ‘uniq’ Command
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1 Finally (at least for now), we’ll look at the ‘uniq’ program.  When
1 sorting data, you will often end up with duplicate lines, lines that are
1 identical.  Usually, all you need is one instance of each line.  This is
1 where ‘uniq’ comes in.  The ‘uniq’ program reads its standard input.  It
1 prints only one copy of each repeated line.  It does have several
1 options.  Later on, we’ll use the ‘-c’ option, which prints each unique
1 line, preceded by a count of the number of times that line occurred in
1 the input.
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